How to react to a Resend request while already resending

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1

Imported from previous forum

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When two fix engines are out-of-sync, the following situation can occur:

FIXA receives a message from FIXB with a SeqNum=1000, whereas it was expecting 990. FIXA asks for a resend of messages 990-0 (0=infinity). Before FIXB is able to react to this resend request, it already has send out a next message with SeqNum=1001. FIXA responds to this with a SECOND resend request 990-0.

Question: What should FIXB do? When it receives the first resend request from FIXA, it starts resending 990,991, etc, but before the resend is finished, it receives the second resend request from FIXA. Should FIXB now
a) Stop the first resend and respond to the second
b) Finish the first resend until the end and then perform the second resend (hence, in the end resending all messages twice)
c) Finish the first resend until the end and ignore the second resend?

The way I understand the Fix documentation, solution b is the correct one. However, this potentially can lead to a lot of unnecessary resends.

Please let me know your opinion/experiences.

Thanks,

Paul van Diepen
VMS-Keytrade

3

Paul, I use method B and put my attention toward maintaining my own out of sequence queue.

Good Luck
Dan

> When two fix engines are out-of-sync, the following situation can occur:
>
> FIXA receives a message from FIXB with a SeqNum=1000, whereas it was expecting 990. FIXA asks for a resend of messages 990-0 (0=infinity). Before FIXB is able to react to this resend request, it already has send out a next message with SeqNum=1001. FIXA responds to this with a SECOND resend request 990-0.
>
> Question: What should FIXB do? When it receives the first resend request from FIXA, it starts resending 990,991, etc, but before the resend is finished, it receives the second resend request from FIXA. Should FIXB now
> a) Stop the first resend and respond to the second
> b) Finish the first resend until the end and then perform the second resend (hence, in the end resending all messages twice)
> c) Finish the first resend until the end and ignore the second resend?
>
> The way I understand the Fix documentation, solution b is the correct one. However, this potentially can lead to a lot of unnecessary resends.
>
> Please let me know your opinion/experiences.
>
> Thanks,
>
> Paul van Diepen
> VMS-Keytrade
>